Griemar, I know what you mean. When I got my first nitro, and saw a K&N air filter, I was ready to order a whole case of them. I've never had a street car that didn't have one, and when running a filter on my race car, it's K&N. The answer is quite simple though, the paper style filter is just not a good design for a nitro engine. The K&N filter will allow fine sediment to enter the engine, which destroys the cylinder wall and the piston. The oiled foam filters do a much better job of filtering the fine sediment, especially the 2 stage filters like the motor saver filters. I've seen engines that have run for 2 bash sessions and been destroyed by the dirt that got into the cylinder. I'm K&N's best spokes person, and personally I don't think they should even advertise them as RC filters because it gives them a bad name. If you were not running in any dirt, and were strictly running your RC's on VERY clean concrete, then I think the K&N MIGHT be ok. But most RC's out there see off-road use or at best dirty asphalt. Trust me, stay away from them. It might be ok, but it's a HUGE risk you'll be taking.